how to program the alt+tab close button in a c#.net winforms application

Question

I have this winform app that tracks battery life, if I close the app during an "alt+tab" (like in the pic below) it closes the app completely.

I want to program the close button (if this is possible) to minimize the app to the system tray instead of closing it completely.

I have not seen any similar solutions for this, all I see is disabling the alt+tab on a winforms app.

I want to do this because if I close the app the battery percentage wont be monitored anymore, I just want to know if this is possible though.

Does this answer your question? How to prevent or block closing a WinForms window? — 41686d6564
Use the FormClosing event as shown in the linked question and set e.Cancel to true after checking any validation logic you need. Make sure not to prevent closing if e.CloseReason == CloseReason.WindowsShutDown so that your program doesn't interrupt the shutdown process. — 41686d6564
@41686d6564 oh yeah, I did not think of the form closing event. Thank you for pointing that out! — JD Dalmao

SlobodanT SlobodanT · Accepted Answer · 2020-12-02T12:27:51

In order to minimize to system tray first add NotifyIcon on your form from Toolbox. And then add this code accordingly.

private System.Windows.Forms.ContextMenu notifyMenu;
private System.Windows.Forms.MenuItem notifyMenuItemClose;
public static bool close = false;

public ApplicationWindow()
{
    InitializeComponent();
}

private void ApplicationWindow_Load(object sender, EventArgs e)
{
    this.notifyMenu = new System.Windows.Forms.ContextMenu();
    this.notifyMenuItemClose = new System.Windows.Forms.MenuItem();
    this.notifyMenu.MenuItems.AddRange( new System.Windows.Forms.MenuItem[] { this.notifyMenuItemClose });
    this.notifyMenuItemClose.Index = 0;
    this.notifyMenuItemClose.Text = "Exit";
    this.notifyMenuItemClose.Click += new System.EventHandler(this.notifyMenuItemClose_Click);
    this.notifyAppIcon.ContextMenu = this.notifyMenu;

}

private void notifyMenuItemClose_Click(object sender, EventArgs e)
{
    close = true;
    this.Close();
}

private void ApplicationWindow_FormClosing(object sender, FormClosingEventArgs e)
{
    if (close)
    {
        e.Cancel = false;
    }
    else
    {
        WindowState = FormWindowState.Minimized;
        e.Cancel = true;
    }
}

private void notifyAppIcon_MouseDoubleClick(object sender, MouseEventArgs e)
{
    if (e.Button==MouseButtons.Left)
    {
        this.Show();
        WindowState = FormWindowState.Normal;
    }
}

how to program the alt+tab close button in a c#.net winforms application

1 Answers